Well for a bit of fun (and considering the Tour de France is heading up the Alpe in a few days), I thought I'd post a follow up chart which covers the power to body mass ratio for the rest of us mere mortals.

Here it is (click to embiggen):

It's not a hard chart to read.

Want to ride up l'Alpe d'Huez in 1 hour dead? Then you'll need to be able to sustain around 3.75 W/kg, give or take depending on the wind. If you are 70kg, then that's around 260-265 watts.

If you know your sustainable power is 3.4W/kg, then you can expect to get up the Alpe in around 66 minutes.

In calculating these values, I've made a few assumptions (listed on the chart), although the relationship between speed and W/kg on steep climbs is not particularly sensitive to those assumptions.

After power and mass, wind has the biggest impact on speeds when climbing. Hence the two extra lines for head and tailwinds.

At my best form*, I would expect to climb it in around 56 minutes.

How fast have you been up l'Alpe?

* My power to body mass ratio for 1-hour at best is ~ 4.2W/kg (based on my racing power at the UCI World Cup this year), but I have to allow a bit of extra mass for my prosthetic leg. I'll get to do it one day.

50:51 on 330 Watts at about 75kg in 2010 for me which matches your chart pretty well.

Regarding one of the comment questions I know that my time would not have made the time cut in the Tour de France ITT that Armstrong won. Zabel was 7 minutes faster I believe. Lots of EPO in that peloton, but still pretty humbling.

RyanGiven the power-duration curve is pretty flat in the range from 50- to 70-minutes, then a good estimate of your functional threshold power would be reasonable place to start. As to what proportion of 20-min power that is, well that's individual, anywhere from 91%-96% is about right.

I haven't had the chance to climb AdH, only estimate what I could do in peak form. That's unlikely to happen any time soon though!